Transesterification of soybean and castor oil with methanol and butanol using heterogeneous basic catalysts to obtain biodiesel

Abstract

This paper focuses on the preparation and characterization of CaO, MgO and ZnO, both bulk and supported on -Al 2 O 3 and their catalytic activity in the transesterification of soybean oil and castor oil with methanol and butanol in order to produce biodiesel. XRD, SEM, CO 2-adsorption followed by TGA and N 2 adsorption have been employed to characterize the prepared catalysts. In supported catalysts, the presence of -Al 2 O 3 improves alcohol dissociation on the superficial basic sites. The first step of the reaction mechanism is then favored (hydrogen abstraction). In the transesterification of castor oil with butanol, MgO/-Al 2 O 3 and ZnO/-Al 2 O 3 catalysts showed high yields to FABE (Fatty Acid Butyl Ester) (97% and 85%, respectively). These last catalysts constitute an efficient alternative for obtaining second-generation biodiesel, taking into account that castor oil is a nonedible source and butanol is an alcohol that can be obtained from biomass.

A sustainable process for biodiesel production using Zn/Mg oxidic species as active, selective and reusable heterogeneous catalysts

“…In order to study the basicity of the prepared catalysts, the amount of adsorbed CO 2 was quantified by thermogravimetric analysis, using a Shimadzu TGA-50 equipment. The analysis conditions are detailed in Navas et al 2018. Scanning electron microscopy images were obtained with a Philips Scanning Electron Microscope 505. The energy dispersive X-ray analysis (EDS) was performed using an EDAX DX PRIME 10 analyzer at a working potential of 15 kV.…”

“…The reaction was conducted in a 250-cm 3 three-necked batch glass reactor, provided with a reflux condenser reflux and a mechanical stirrer. Alcohol/oil molar ratio, catalyst amount and reaction temperature were established at 6:1; 5 wt%, and 60 °C for methanol and 80 °C for butanol (Navas et al 2018). These values were determined from a previous optimization study on the soybean-methanol oil system carried out by our research group (Sánchez et al 2014).…”

Development of castor oil–based polymers: A review

“…The transesterification reaction is carried out usually with homogenous catalysts either acid or base. The base catalysts (usually KOH or NaOH) increases the reaction rate extensively, but they pose the challenge of separation after use, the formation of unwanted by‐products, and soaps . As a solution to this challenge, heterogeneous catalysts such as CaO, BaO, ZnO, and SrO are used.…”

“…As a solution to this challenge, heterogeneous catalysts such as CaO, BaO, ZnO, and SrO are used. ZnO is fit for transesterification of vegetable oils with a high content of free fatty acids as it is an amphoteric oxide …”

A green route for biodiesel production from waste cooking oil over base heterogeneous catalyst

“…Unfortunately, these fuel sources are running out in the near future due to increasing energy consumption and their limit sources . Moreover, the combustion of these fossil fuels adds a huge amount of carbon dioxide (about 98%) into the atmosphere, causing serious threats to environment and human society . Keeping in view the above two points, renewable energy sources are encouraged to substitute the petroleum‐derived diesel.…”